diff --git a/tests/OTPTest.php b/tests/OTPTest.php
new file mode 100644
index 0000000..cba59c6
--- /dev/null
+++ b/tests/OTPTest.php
@@ -0,0 +1,98 @@
+<?php
+
+namespace Craftsys\Tests\Msg91;
+
+use Craftsys\Msg91\Client;
+use GuzzleHttp\Client as HttpClient;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Middleware;
+use Craftsys\Msg91\Support\Response as CraftsysResponse;
+
+class OTPTest extends TestCase
+{
+    protected $container = [];
+
+    /**
+     * Define environment setup.
+     *
+     * @param  \Illuminate\Foundation\Application $app
+     *
+     * @return void
+     */
+    protected function getEnvironmentSetUp($app)
+    {
+        $app['config']->set('services.msg91.key', 'my_api_key');
+    }
+
+    public function test_send_otp()
+    {
+        /** @var \Craftsys\Msg91\Client $client */
+        $client = app(Client::class);
+        $response = $client
+            ->setHttpClient($this->createMockHttpClient())
+            ->otp()
+            ->to(91999999999)
+            ->send();
+
+        $this->assertInstanceOf(CraftsysResponse::class, $response);
+
+        // make sure there was exacly on request
+        $this->assertCount(1, $this->container);
+        $this->container = [];
+    }
+
+    public function test_resend_otp()
+    {
+        /** @var \Craftsys\Msg91\Client $client */
+        $client = app(Client::class);
+        $response = $client
+            ->setHttpClient($this->createMockHttpClient())
+            ->otp()
+            ->to(91999999999)
+            ->viaText()
+            ->send();
+
+        $this->assertInstanceOf(CraftsysResponse::class, $response);
+
+        // make sure there was exacly on request
+        $this->assertCount(1, $this->container);
+        $this->container = [];
+    }
+
+    public function test_verify_otp()
+    {
+        /** @var \Craftsys\Msg91\Client $client */
+        $client = app(Client::class);
+        $response = $client
+            ->setHttpClient($this->createMockHttpClient())
+            ->otp(123123)
+            ->to(91999999999)
+            ->verify();
+
+        $this->assertInstanceOf(CraftsysResponse::class, $response);
+
+        // make sure there was exacly on request
+        $this->assertCount(1, $this->container);
+        $this->container = [];
+    }
+
+    protected function createMockHttpClient(
+        $status_code = 200,
+        $body = [
+            "type" => "success", "message" => "Send successfully"
+        ]
+    ): HttpClient {
+        $history = Middleware::history($this->container);
+        $mock = new MockHandler([
+            new Response($status_code, [], json_encode($body)),
+        ]);
+
+        $handler = HandlerStack::create($mock);
+        $handler->push($history);
+
+        $client = new HttpClient(['handler' => $handler]);
+        return $client;
+    }
+}
diff --git a/tests/SMSTest.php b/tests/SMSTest.php
new file mode 100644
index 0000000..ae9d0d4
--- /dev/null
+++ b/tests/SMSTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Craftsys\Tests\Msg91;
+
+use Craftsys\Msg91\Client;
+use GuzzleHttp\Client as HttpClient;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Middleware;
+use Craftsys\Msg91\Support\Response as CraftsysResponse;
+
+class SMSTest extends TestCase
+{
+    protected $container = [];
+
+    /**
+     * Define environment setup.
+     *
+     * @param  \Illuminate\Foundation\Application $app
+     *
+     * @return void
+     */
+    protected function getEnvironmentSetUp($app)
+    {
+        $app['config']->set('services.msg91.key', 'my_api_key');
+    }
+
+    public function test_send_otp()
+    {
+        /** @var \Craftsys\Msg91\Client $client */
+        $client = app(Client::class);
+        $response = $client
+            ->setHttpClient($this->createMockHttpClient())
+            ->sms()
+            ->flow('flow_id')
+            ->to(91999999999)
+            ->variable('day', 'this')
+            ->send();
+
+        $this->assertInstanceOf(CraftsysResponse::class, $response);
+
+        // make sure there was exacly on request
+        $this->assertCount(1, $this->container);
+        $this->container = [];
+    }
+
+    protected function createMockHttpClient(
+        $status_code = 200,
+        $body = [
+            "type" => "success", "message" => "Send successfully"
+        ]
+    ): HttpClient {
+        $history = Middleware::history($this->container);
+        $mock = new MockHandler([
+            new Response($status_code, [], json_encode($body)),
+        ]);
+
+        $handler = HandlerStack::create($mock);
+        $handler->push($history);
+
+        $client = new HttpClient(['handler' => $handler]);
+        return $client;
+    }
+}